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opencc-zeroDec 2014View details →

Data from: The challenge of accurately documenting bee species richness in agroecosystems: bee diversity in eastern apple orchards

Bees are important pollinators of agricultural crops, and bee diversity has been shown to be closely associated with pollination, a valuable ecosystem service. Higher functional diversity and species richness of bees have been shown to lead to higher crop yield. Bees simultaneously represent a mega-diverse taxon that is extremely challenging to sample thoroughly and an important group to understand because of pollination services. We sampled bees visiting apple blossoms in 28 orchards over 6 years. We used species rarefaction analyses to test for the completeness of sampling and the relationship between species richness and sampling effort, orchard size, and percent agriculture in the surrounding landscape. We performed more than 190 h of sampling, collecting 11,219 specimens representing 104 species. Despite the sampling intensity, we captured <75% of expected species richness at more than half of the sites. For most of these, the variation in bee community composition between years was greater than among sites. Species richness was influenced by percent agriculture, orchard size, and sampling effort, but we found no factors explaining the difference between observed and expected species richness. Competition between honeybees and wild bees did not appear to be a factor, as we found no correlation between honeybee and wild bee abundance. Our study shows that the pollinator fauna of agroecosystems can be diverse and challenging to thoroughly sample. We demonstrate that there is high temporal variation in community composition and that sites vary widely in the sampling effort required to fully describe their diversity. In order to maximize pollination services provided by wild bee species, we must first accurately estimate species richness. For researchers interested in providing this estimate, we recommend multiyear studies and rarefaction analyses to quantify the gap between observed and expected species richness.

opencc-zeroFeb 2020View details →

Citizen science improves our understanding of the impact of soil management on wild pollinator abundance in agroecosystems

Native bees provide essential pollination services in both natural and managed ecosystems. However, declines in native bee species highlight the need for increased understanding of land management methods that can promote healthy, persistent populations and diverse communities. This can be challenging and costly using traditional scientific methods, but citizen science can overcome many limitations. In this study, we examined the distribution and abundance of an agriculturally important wild bee species, the squash bee (Eucera (Peponapis) pruinosa, Hymenoptera: Apidae). They are ground nesting, specialist bees that depend on cultivated varieties of Cucurbita (squash, pumpkins, gourds). The intimate relationship between squash bees and their host plants suggests that they are likely sensitive to farm management practices, particularly those that disturb the soil. In this study, citizen scientists across Michigan used a smartphone application to submit field management and bee observation data. Survey results indicated that squash bees occupy a wide geographic range and are more abundant in farms with reduced soil disturbance. Citizen science provided a cheap, effective method for examining impacts of farm management practices on squash bees and could be a valuable tool for monitoring and conserving other native pollinators.

opencc-zeroDec 2014View details →

Data from: Application of ITS2 metabarcoding to determine the provenance of pollen collected by honey bees in an agroecosystem

Premise of the study: Melissopalynology, the identification of bee-collected pollen, provides insight into the flowers exploited by foraging bees. Information provided by melissopalynology could guide floral enrichment efforts aimed at supporting pollinators, but it has rarely been used because traditional methods of pollen identification are laborious and require expert knowledge. We approach melissopalynology in a novel way, employing a molecular method to study the pollen foraging of honey bees (Apis mellifera) in a landscape dominated by field crops, and compare these results to those obtained by microscopic melissopalynology. Methods: Pollen was collected from honey bee colonies in Madison County, Ohio, USA, during a two-week period in mid-spring and identified using microscopic methods and ITS2 metabarcoding. Results: Metabarcoding identified 19 plant families and exhibited sensitivity for identifying the taxa present in large and diverse pollen samples relative to microscopy, which identified eight families. The bulk of pollen collected by honey bees was from trees (Sapindaceae, Oleaceae, and Rosaceae), although dandelion (Taraxacum officinale) and mustard (Brassicaceae) pollen were also abundant. Discussion: For quantitative analysis of pollen, using both metabarcoding and microscopic identification is superior to either individual method. For qualitative analysis, ITS2 metabarcoding is superior, providing heightened sensitivity and genus-level resolution.

opencc-zeroJul 2019View details →

Data from: Feedbacks between nitrogen fixation and soil organic matter increase ecosystem functions in diversified agroecosystems

Nitrogen (N) losses from intensified agriculture are a major cause of global change, due to nitrate (NO3-) export and the eutrophication of aquatic systems as well as emissions of nitrous oxide (N2O) into the atmosphere. Diversified agroecosystems with legume cover crops couple N and carbon (C) inputs to soil and reduce N pollution, but there is a need to identify controls on legume N2 fixation across ecosystems with variable soil conditions. Here, I tested the hypothesis that N mineralization from turnover of soil organic matter (SOM) regulates legume N2 fixation across 10 farms that spanned a gradient of SOM levels. I separated soil samples into two SOM fractions, based on size and density, which are indicators of soil nutrient cycling and N availability (free particulate organic matter and intra-aggregate particulate organic matter (POM)). This study indicates downregulation of legume N2 fixation in diversified agroecosystems with increasing N availability in intra-aggregate POM and increasing N mineralization. Intercropping the legume with a grass weakened the relationship between N in POM and N2 fixation due to N assimilation by the grass. Further, mean rates of N and C mineralization across sites increased with two seasons of a legume-grass cover crop mixture, which could enhance this stabilizing feedback between soil N availability and N2 fixation over time. These results suggest a potential mechanism for the diversity-ecosystem function relationships measured in long-term studies of agroecosystems, in which regular use of legume cover crops increases total soil organic C and N and reduces the environmental costs of crop production.

opencc-zeroDec 2017View details →

Data from: Crop rotational diversity enhances belowground communities and functions in an agroecosystem

Biodiversity loss, an important consequence of agricultural intensification, can lead to reductions in agroecosystem functions and services. Increasing crop diversity through rotation may alleviate these negative consequences by restoring positive aboveground–belowground interactions. Positive impacts of aboveground biodiversity on belowground communities and processes have primarily been observed in natural systems. Here, we test for the effects of increased diversity in an agroecosystem, where plant diversity is increased over time through crop rotation. As crop diversity increased from one to five species, distinct soil microbial communities were related to increases in soil aggregation, organic carbon, total nitrogen, microbial activity and decreases in the carbon-to-nitrogen acquiring enzyme activity ratio. This study indicates positive biodiversity–function relationships in agroecosystems, driven by interactions between rotational and microbial diversity. By increasing the quantity, quality and chemical diversity of residues, high diversity rotations can sustain soil biological communities, with positive effects on soil organic matter and soil fertility.

opencc-zeroDec 2018View details →

Data from: Contribution of predation to the biological control of a key herbivorous pest in citrus agroecosystems

Biological control has traditionally simplified the view of trophic relationships between herbivorous pests and their natural enemies in agriculture. The success or failure of this pest management strategy is still mainly attributed to the ability of a few key natural enemies to suppress the pest density. For example, successful regulation of the California red scale (Aonidiella aurantii) a key citrus pest, is generally credited to specific parasitoids of the Aphytis genus. Currently, research is revealing how herbivore regulation in agroecosystems can be alternatively achieved with a greater number of trophic associations within the system. The goals of the present study were: i) to unravel species‐specific trophic links between A. aurantii, and its natural enemies in citrus agroecosystems, and ii) to assess their contribution to control of A. aurantii. Predation and parasitism of this herbivorous pest were assessed through exclusion experiments. Species‐specific trophic links between this herbivorous pest and its natural enemies were studied using gut‐content analysis of field collected predators employing prey specific DNA molecular markers. Relative predation rates of the species involved in A. aurantii regulation were estimated. Predation was found to be the main biotic component of A. aurantii mortality, causing reductions of more than 75% in recently settled cohorts. Aonidiella aurantii DNA was detected in the digestive system of 11 species of predators. Generalist and stenophagous predators, mainly associated with other citrus pests such as aphids, proved to be the most important biological control agents of this pest. Complex trophic relationships, such as apparent competition between two key citrus pests, were revealed. The present study highlights the role of predation as biotic mortality factor of key pests in perennial agroecosystems; wherein, it is a rich complex of indigenous or naturalized generalist predators that are primarily responsible for this mortality. The results herein presented may therefore offer another perspective on the biological control of one of the key worldwide citrus pests; at least in those regions where specific parasitoids are not able to successfully regulate the scale populations.

opennotspecifiedFeb 2024View details →

Figure 3 in Phenology and impact of abiotic factors with a temporal lag on the abundance of common crab spider, Xysticus cristatus (Clerck, 1757) (Araneae: Thomisidae) in the agroecosystems of Kashmir

Figure 3. Carapace width frequency distribution of the monthly catches of Xysticus cristatus from April to September 2019.

opennotspecifiedFeb 2024View details →

Figure 4 in Phenology and impact of abiotic factors with a temporal lag on the abundance of common crab spider, Xysticus cristatus (Clerck, 1757) (Araneae: Thomisidae) in the agroecosystems of Kashmir

Figure 4. Activity pattern in terms of number of females caught in pitfall traps and abdominal width from March to July 2019 during the reproductive period in females of Xysticus cristatus.

opennotspecifiedFeb 2024View details →

Figure 2 in Phenology and impact of abiotic factors with a temporal lag on the abundance of common crab spider, Xysticus cristatus (Clerck, 1757) (Araneae: Thomisidae) in the agroecosystems of Kashmir

Figure 2. Circular histograms illustrating the frequency of age structure established for the population of Xysticus cristatus in agroecosystems of Kashmir from March 2018 to February 2020. The angular mean or direction of the data is indicated by the grey line vector inside the circle. The 95% confidence interval is indicated by the transverse line in the sector outside the circle.

opencc-zeroNov 2021View details →

Persistence of seed dispersal in agroecosystems: effects of landscape modification and intensive soil management practices in avian frugivores, frugivory and seed deposition in olive croplands

Farming impacts on animal-mediated seed dispersal through mechanisms operating at least at two spatial scales: first, at the landscape scale, through habitat loss and land conversion to agriculture/livestock grazing, and second, by local intensification (farm scale) of the agricultural practices. Nonetheless, these two scales of farming impact on the seed dispersal function have been rarely integrated. In particular, studies evaluating the effect of agriculture in the seed dispersal function of frugivorous birds in Mediterranean ecosystems are lacking. We evaluate the role of the landscape transformation, from fruit-rich woodland habitats to olive grove landscapes, together with the local intensive practices of soil management on the persistence of the seed dispersal function for Mediterranean fleshy-fruited plants in olive landscapes of south Spain. We used bird censuses, mist-nets and seed traps to characterize avian frugivore assemblages, frugivory, and seed deposition in seminatural woodland habitat (SNWH) patches and olive fields of 40 olives farms of 20 localities distributed across the whole range of olive cultivation in Andalusia (southern Spain). We found that despite of a still remarkable dispersal function in olive grove landscapes, avian frugivore abundance and diversity, frugivory, and seed arrival decreased in olive fields compared to SNWH patches. Likewise, SNWH cover loss and/or olive growing expansion decreased avian frugivory and seed arrival. Interestingly, habitat effects in the olive farms often depended on the landscape context. In particular, less diverse fruit-eating bird assemblages pooled in SNWH patches as olive grove cover increased or SNWH decreased in the landscape, while remained relatively invariant in the olive fields. Finally, compared to conventional intensive agriculture, low-intensity management increased frugivory and seed deposition. We conclude that olive fields are less permeable to frugivores than expected by its agroforest-like nature, and that presence of SNWH patches is crucial for the maintenance of frugivory and seed dispersal in agricultural landscapes. Results evidence that woodland habitat loss by olive expansion and the intensive practices seriously threaten the dispersal service in olive-dominated landscapes. Maintenance, restoration and promotion of woodland patches should be prioritized for the conservation of the seed dispersal service and for enhancing the functional connectivity in human-shaped olive landscapes.

opencc-zeroDec 2021View details →

Data-Linking remote sensing data to the estimation of pollination services in agroecosystems

Wild bees are key providers of pollination services in agroecosystems. The abundance of these pollinators, and the service they provide, relies on the availability of supporting resources in the landscape. Because of this, spatially explicit models have been developed to quantify wild bee abundance and pollination services in food crops, while accounting for the influence of locally available foraging and nesting resources. However, model implementation is limited by the availability of land cover maps and experts on pollinators capable of establishing the quality of local habitats for pollinators. In this study, we present how remote sensing data can be linked to the estimation of wild bee abundance, and act as an alternative to the conventional use of land cover maps and local expertise in spatially explicit models estimating pollination services. For this, we used landscape characteristics derived from remote sensors to qualify nesting resources in the landscape and thereafter estimate the delivery of pollination services by mining bees (Andrena spp.) in 30 fruit orchards located in the Flemish region of Belgium. Mining bees were selected for this study for their major role as local pollinators and underground nesting habits. Estimated pollination services were compared with those derived from conventional qualifications of nesting resources and showed no significant differences (P=0.68) in the amount of explained variation in activity of mining bees on the studied orchards. Estimates derived from remote sensing data and conventional inputs explaining 69% and 72% of the total variation, respectively. These results confirmed that remote sensing data can deliver nesting suitability characterizations suitable for the estimation of pollination services, This research also illustrates the relevance of nesting resources and highlights the importance of considering soil resources in the estimation of pollination services provided by pollinators like mining bees. Our results support the development of holistic agro-environmental policies that rely on the use of modern tools like remote sensors and promote pollinators by considering nesting resources.

opencc-zeroJan 2022View details →

Influence of habitat quality and resource density on breeding-season female monarch butterfly (Danaus plexippus) movement and space use in north-central USA agroecosystem landscapes

<ol> <li> The eastern North American monarch butterfly is at risk of quasi-extinction due, in part, to the loss of breeding habitat in agricultural landscapes of the USA Midwest. Because adult females are not patch residents, egg abundance and distribution across the landscape are a function of their perceptual range, flight directionality, and flight step lengths. Conservation actions that account for habitat use in agricultural landscapes can enhance functional connectivity.</li> <li>Field-captured females (n=114) were released in a 64-ha area containing restored prairies, grass-dominated fields, and crop fields in Floyd County, Iowa, USA, and two 1,000 m linear north-south sections of grass-dominated roadside along secondary roads (~ 35 ha) with different proximity to prairie habitat in rural Story County, Iowa. Radio-tagged or untagged monarchs were released in areas with high-density, low-density, and zero density of forage and oviposition resources, as well as on habitat edges between high and zero-density habitats. Monarchs were observed for one hour. Radio-tagged individuals that flew beyond visual detection were relocated using handheld radio telemetry.</li> <li>Monarchs moved within and between habitat classes and typically performed up-wind search behavior. Monarchs successfully located resources, with some flying over 500 m to find high-density areas, providing evidence that the monarch's perceptual distance is > 100 m. Regardless of habitat class or field site, most step lengths were < 50 m, and turn angles were directional. Large steps (≥ 50 m) crossing habitat boundaries occurred with approximately half of the monarchs, which may indicate initiation of long-range searches for suitable habitat, consistent with their vagile behavior. Establishing habitat patches 50 m apart in agricultural landscapes would facilitate efficient movement.</li> <li>This study provides an extensive dataset of directly observed breeding-season monarch butterflies to assess the utilization of agricultural landscapes. Documentation of step lengths > 50 m in complex, agricultural landscapes would not have been possible without the aid of radio telemetry. Results provide improved estimates of perceptual range and flight patterns within and between habitat patches that support models that simulate natural population dynamics to enable conservation planning at a landscape scale.</li> </ol>

FIGURE 59 in Complementary description of three species of Steneotarsonemus (Acari: Tarsonemidae) from rice agroecosystems of Eastern India with notes on their taxonomic status, spatial distribution, intraspecific variation and species composition

FIGURE 59. Abundance of Steneotarsonemus spinki vs S. subfurcatus within the species complex of rice sheath mites across the different agroecological zones of West Bengal. Equal letters for each species category do not differ significantly at p<0.05.

FIGURE 58 in Complementary description of three species of Steneotarsonemus (Acari: Tarsonemidae) from rice agroecosystems of Eastern India with notes on their taxonomic status, spatial distribution, intraspecific variation and species composition

FIGURE 58. Results of Non-metric multidimensional scaling (NMDS), using Bary Curtis matrix, applied to test similarity in morphological variant composition of Steneotarsonemus spinki males in Eastern India (The states are colour coded as green: West Bengal; Blue: Orissa; Yellow: Tripura; Red: Manipur).

FIGURE 57 in Complementary description of three species of Steneotarsonemus (Acari: Tarsonemidae) from rice agroecosystems of Eastern India with notes on their taxonomic status, spatial distribution, intraspecific variation and species composition

FIGURE 57. Abundance of morphological variants (mean±S.E.) of Steneotarsonemus spinki male in Eastern India. Mean followed by same letter do not differ significantly at 5% level of Significance.

FIGURES 41.—47. Steneotarsonemus spinki 41 in Complementary description of three species of Steneotarsonemus (Acari: Tarsonemidae) from rice agroecosystems of Eastern India with notes on their taxonomic status, spatial distribution, intraspecific variation and species composition

FIGURES 41.—47. Steneotarsonemus spinki 41—Dorsal surface (female), 42—Ventral surface (female), 43. Dorsal surface (male), 44—Ventral surface (male), 45. Leg IV (male, variant S), 46. Leg IV (male, variant I), 47. Leg IV (male, variant L).

FIGURES 38.—40 in Complementary description of three species of Steneotarsonemus (Acari: Tarsonemidae) from rice agroecosystems of Eastern India with notes on their taxonomic status, spatial distribution, intraspecific variation and species composition

FIGURES 38.—40. Three variants of Steneotarsonemus spinki (male Leg IV). 38.Variant S, 49. Variant I and 40. Variant L (top to bottom).

FIGURES 53.—56. Steneotarsonemus subfurcatus 53 in Complementary description of three species of Steneotarsonemus (Acari: Tarsonemidae) from rice agroecosystems of Eastern India with notes on their taxonomic status, spatial distribution, intraspecific variation and species composition

FIGURES 53.—56. Steneotarsonemus subfurcatus 53—Dorsal surface (female), 54—Ventral surface (female), 55. Dorsal surface (male), 56—Ventral surface (male).

FIGURES 28.—31 in Complementary description of three species of Steneotarsonemus (Acari: Tarsonemidae) from rice agroecosystems of Eastern India with notes on their taxonomic status, spatial distribution, intraspecific variation and species composition

FIGURES 28.—31. Steneotarsonemus subfurcatus (female). 28.—leg I, 29.—leg II, 30.—leg III, 31.—leg IV.

FIGURES 34.—37 in Complementary description of three species of Steneotarsonemus (Acari: Tarsonemidae) from rice agroecosystems of Eastern India with notes on their taxonomic status, spatial distribution, intraspecific variation and species composition

FIGURES 34.—37. Steneotarsonemus subfurcatus (male). 34.—leg I, 35.—leg II, 36.—leg III, 37.—leg IV.